Flow metering and retention system

ABSTRACT

A flow metering and retention system includes a first disk that is annular in shape surrounding a centerline and extending axially along the centerline, a first coverplate axially rearward of the first disk with the first coverplate having an axially rearward extending arm, a second disk that is annular in shape surrounding the centerline and rearward of the first coverplate, a second coverplate at least partially between the first coverplate and the second disk; and a ring adjacent to the radially outer side of the slot of the second disk. The second disk has a slot into which the arm of the first coverplate extends with the slot having a radially outer side and a radially inner side, and the ring is configured to meter air flowing between the radially outer side of the slot and the arm of the first coverplate.

STATEMENT OF GOVERNMENT INTEREST

This invention was made with government support under W58RGZ-16-C-0046awarded by the United States Army. The government has certain rights inthe invention.

BACKGROUND

The present invention relates to metering cooling air in a gas turbineengine, and in particular, to the use of a ring to meter cooling air andretain components in a gas turbine engine.

In general, gas turbine engines combust a mixture of compressed air andfuel to produce hot combustion gases. The combustion gases may flowthrough one or more turbine stages to generate power for a load and/orcompressor. The combination of hot gases and high pressures can causestress and wear of components in the turbine. To reduce the stress andwear, cooling air flows through parts of the turbine, such as theinterturbine area between the turbine disks. Between the turbine disks,high pressure of the cooling air may need to be maintained in order toprovide increased cooling capabilities. To maintain a high pressure, thecooling air can be metered. Further, each turbine disk may include acoverplate adjacent to and connected to a side of a respective turbinedisk. While various devices can be used to connect the coverplates tothe turbine disk, limitations in the space within the interturbine areamakes metering of the cooling air and retention of the coverplateadjacent to the turbine disk difficult.

SUMMARY

A system for a gas turbine engine includes a high pressure turbine disk,a high pressure turbine coverplate, and low pressure turbine disk, a lowpressure turbine coverplate, an interface between the low pressureturbine disk and the low pressure turbine coverplate, and a ring. Thehigh pressure turbine coverplate is axially rearward of the highpressure turbine disk and has an arm that extends axially rearward. Thelow pressure turbine disk is axially rearward of the high pressureturbine coverplate and has a slot into which the arm of the highpressure turbine coverplate extends. The low pressure turbine coverplateis at least partially between the high pressure turbine coverplate andthe low pressure turbine disk. The interface is radially outward fromthe arm of the high pressure turbine coverplate and has a groove. Thering is within the groove at the interface and extending radially inwardtowards the arm of the high pressure turbine coverplate with the ringbeing configured to prevent axial movement of the low pressure turbinecoverplate relative to the low pressure turbine and to form a firstmetering point to meter air flowing between the high pressure turbinecoverplate and the low pressure turbine disk.

A flow metering and retention system includes a first disk that isannular in shape surrounding a centerline and extending axially alongthe centerline, a first coverplate axially rearward of the first diskwith the first coverplate having an axially rearward extending arm, asecond disk that is annular in shape surrounding the centerline andrearward of the first coverplate, a second coverplate at least partiallybetween the first coverplate and the second disk; and a ring adjacent tothe radially outer side of the slot of the second disk. The second diskhas a slot into which the arm of the first coverplate extends with theslot having a radially outer side and a radially inner side, and thering is configured to meter air flowing between the radially outer sideof the slot and the arm of the first coverplate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an interturbine area of a gasturbine engine.

FIG. 2A is an enlarged cross-sectional view of a flow metering andretention system in the interturbine area of the gas turbine engine.

FIG. 2B is a first cross-sectional perspective view of the flow meteringand retention system.

FIG. 3 is a second cross-sectional perspective view of the flow meteringand retention system.

DETAILED DESCRIPTION

A flow metering and retention system in an interturbine area of a gasturbine engine is disclosed herein. The flow metering and retentionsystem includes a slot in a low pressure turbine (“LPT”) disk and an armon a high pressure turbine (“HPT”) coverplate that extends into theslot. On a radially outer side of the slot is a ring that can bepositioned within a groove in interlocking teeth on the LPT disk and anLPT coverplate. The ring and the placement of the ring relative to thearm of the HPT coverplate provides at least three functions in the flowmetering and retention system. First, the ring within the groove in theteeth of the LPT disk and LPT coverplate provides axial retention of theLPT disk and LPT coverplate to ensure the two components remain adjacentto one another. The teeth of the LPT disk and LPT coverplate arecircumferentially alternating, providing circumferential retention ofthe LPT disk and LPT coverplate to ensure the two components rotate inunison, and the LPT disk is at least partially radially within the LPTcoverplate, providing radial retention to ensure the two componentsremain radially adjacent to one another. Thus, the ring and surroundingcomponents ensure that the LPT coverplate is retained in relation to theLPT disk. Second, the ring extends radially inward into a gap betweenthe radially outer side of the slot and the arm of the HPT coverplate.The inward extending ring creates a first metering point of cooling airflowing within the interturbine area to ensure the pressure of thatcooling air within the interturbine area remains elevated to providesufficient cooling to the LPT disk, the LPT coverplate, and the othercomponents within the interturbine area. Third, the ring acts as abuffer between the rotating LPT disk and the nonrotating or oppositelyrotating HPT coverplate to prevent the two components from contactingone another and becoming damaged. While this disclosure discusses theflow metering and retention system as being located between two rotatingcomponents rotating in an opposite direction from one another, otherembodiments of the flow metering and retention system can be utilizedwith one or both components being static/nonrotating.

FIG. 1 is a cross-sectional view of an interturbine area of a gasturbine engine. Gas turbine engine 10 includes interturbine area 12between high pressure turbine disk 14 and low pressure turbine disk 16.Interturbine area 12, HPT disk 14, and LPT disk 16 are radially outwardfrom shaft 18, which extends along an axial centerline C of gas turbineengine 10. HPT disk 14 includes radially outer side 14 a, radially innerside 14 b, an axially forward side (not shown), and axially rearwardside 14 c with HPT blades 20 on radially outer side 14 a. LPT disk 16includes radially outer side 16 a, radially inner side 16 b, axiallyforward side 16 c, and an axially rearward side (not shown) with slot 17on axially forward side 16 c and LPT blades 22 on radially outer side 16a. Interturbine area 12 includes HPT coverplate 24 (with arm 25), LPTcoverplate 26 (with at least one cooling air hole 27), and tube 28. HPTdisk 14 and HPT coverplate 24 interact with one another at HPT interface30, while LPT disk 16 and LPT coverplate 26 interact with one another atLPT interface 32.

Although the disclosed non-limiting embodiment depicts a gas turbineengine, it should be understood that the concepts described herein arenot limited to use with gas turbine engines as the teachings may beapplied to other types of machines. Further, while this disclosuredetails the use of a flow metering and retention system between a HPTdisk and a LPT disk, the configuration described herein can be utilizedin other sections of the gas turbine engine. It should be furtherunderstood that the disclosed non-limiting embodiment provides generallya flow metering and retention system that is suitable for many types ofrotating or rotary machines as known to those of ordinary skill in theart.

Shaft 18 extends along centerline C of gas turbine engine 10 and rotatesto transmit power between various components of gas turbine engine 10.Shaft 18 can be a low speed shaft/spool, a high speed shaft/spool, oranother configuration. However, as shown in the disclosed embodiment,shaft 18 is adjacent to and interlocks with radially inner side 16 b ofLPT disk 16, so shaft 18 is a low speed shaft. Shaft 18 can interlockwith LPT disk 16 through radially extending fingers that interact withfeatures on radially inner side 16 b of LPT disk 16 to force shaft 18 torotate in unison with LPT disk 16 to transfer power along shaft 18 (orvice-versa).

HPT disk 14 is an annular turbine disk that surrounds and is radiallyoutward from shaft 18. HPT disk 14 is axially forward from LPT disk 16.HPT disk 14 is not connected to shaft 18 and does not rotate in unisonwith shaft 18 and LPT disk 16. Rather, HPT disk 14 is configured torotate either in an opposite direction to shaft 18 and LPT disk 16 or ata speed that is different than a speed of rotation of shaft 18 and LPTdisk 16 (including HPT disk 14 being nonrotating while LPT disk 16 andshaft 18 rotating in unison). HPT disk 14 includes HPT blades 20 onradially outer side 14 a that extract power from a gas flowing through agas path within gas turbine engine 10. While not shown in FIG. 1, HPTdisk 14 can be connected to a high speed shaft or another component atradially inner side 14 b near the axially forward side of HPT disk 14 oranother location to transfer power to other components of gas turbineengine 10. HPT disk 14 has axially rearward side 14 c that forms anaxially forward boundary of interturbine area 12. HPT disk 14 alsoincludes the axially forward side that is not shown in FIG. 1 but can besimilar in configuration to axially rearward side 14 c. HPT disk 14 canhave a cross section that is generally thicker (i.e., extends a longerdistance in the axial direction) near radially inner side 14 b than nearradially outer side 14 a. However, HPT disk 14 as shown has a crosssection that curves axially forward along axially rearward side 14 c. Atradially outer side 14 a, HPT disk 14 can include features that allowfor the attachment of HPT blades 20 to HPT disk 14.

On radially inner side 14 b near axially rearward side 14 c, HPT disk 14includes teeth that extend radially inward at HPT interface 30 tointerlock with teeth of HPT coverplate 24 to retain HPT coverplate 24adjacent to axially rearward side 14 c of HPT disk 14 (i.e., to preventmovement of HPT coverplate 24 relative to HPT disk 14). Duringoperation, HPT disk 14 can experience elevated temperatures due to therotation of HPT disk 14 and other factors. HPT disk 14 can include otherfeatures and configurations not shown or explicitly discussed in thisdisclosure.

Adjacent to axially rearward side 14 c of HPT disk 14 is HPT coverplate24, which extends radially from radially outer side 14 a of HPT disk 14(adjacent HPT blades 20) to HPT interface 30. HPT coverplate 24 caninclude teeth that interlock with HPT disk 14 (i.e., the teeth of HPTdisk 14) at HPT interface 20 so that HPT coverplate 24 rotates in unisonwith HPT disk 14 and does not move independently from HPT disk 14. HPTcoverplate 24 can include sealing features, such as feather seals, tohelp seal the rotating HPT coverplate 24 with nonrotating (or oppositelyrotating) tube 28 and/or other components of gas turbine engine 10. HPTcoverplate 24 includes arm 25, which extends axially rearward towardsLPT disk 16.

Arm 25 is at radially inner end of HPT coverplate 24 and extends axiallyrearward into slot 17 in LPT disk 16. Arm 25 and slot 17 form a portionof the flow metering and retention system that will be discussed withregards to FIGS. 2A, 2B, and 3. HPT coverplate 24 can include otherfeatures and configurations not shown or explicitly discussed in thisdisclosure.

LPT disk 16 is an annular turbine disk that surrounds and is radiallyoutward from shaft 18. LPT disk 16 is axially rearward from HPT disk 14,and LPT disk 16 is configured to rotate in unison with shaft 18 andtransfer power to other components of gas turbine engine 10. LPT disk 16includes LPT blades 22 on radially outer side 16 a that extract powerfrom a gas flowing through a gas path within gas turbine engine 10. Asmentioned above, LPT disk 16 interlocks with shaft 18 at radially innerside 16 b. LPT disk 16 has axially forward side 16 c that forms anaxially rearward boundary of interturbine area 12. LPT disk 16 alsoincludes the axially rearward side that is not shown in FIG. 1 but canbe similar in configuration to axially forward side 16 c. LPT disk 16can have a cross section that is generally thicker (i.e., extends alonger distance in the axial direction) near radially inner side 16 bthan near radially outer side 16 a. However, LPT disk 16 as shown has across section that curves axially rearward along axially forward side 16c. At radially outer side 16 a, LPT disk 16 can include features thatallow for the attachment of LPT blades 22 to LPT disk 16.

On axially rearward side 16 c near radially inner side 16 b, LPT disk 16includes teeth that extend axially forward at LPT interface 32 tointerlock with teeth of LPT coverplate 26 (as will be discussed withregards to FIGS. 2A, 2B, and 3). The LPT disk 16 teeth can also includea feature, such as a groove, configured to accommodate a ring, such as aspiral ring seal. Additionally, at the intersection of radially innerside 16 b and axially forward side 16 c is an axially forward extendingmember (which can include features that interact and interlock withshaft 18 on radially inner side 16 b). This member, along with LPTinterface 32, form slot 17 into which arm 25 of HPT coverplate 24extends. During operation, LPT disk 16 can experience elevatedtemperatures due to the rotation of LPT disk 16 and other factors. LPTdisk 16 can include other features and configurations not shown orexplicitly discussed in this disclosure.

Adjacent to axially forward side 16 c of LPT disk 16 is LPT coverplate26, which extends radially from radially outer side 16 a of LPT disk 16(adjacent LPT blades 22) to LPT interface 32. LPT coverplate 26 caninclude teeth that interlock with LPT disk 16 (i.e., the teeth of LPTdisk 16) at LPT interface 32 so that LPT coverplate 26 rotates in unisonwith LPT disk 16 and shaft 18. The LPT coverplate 26 teeth can alsoinclude a feature, such as a groove, configured to accommodate a ring,such as a spiral ring seal. LPT coverplate 26 can include sealingfeatures, such as feather seals, to help seal the rotating LPTcoverplate 26 with nonrotating (or oppositely rotating) tube 28 and/orother components of gas turbine engine 10. Further, LPT coverplate 26can include at least one cooling air hole 27 that is configured to allowcooling air (or another fluid) to access/reach LPT disk 16 to cool LPTdisk 16. LPT coverplate 26 can include other features and configurationsnot shown or explicitly discussed in this disclosure.

Tube 28 is within interturbine area 12 and is positioned between HPTcoverplate 24 and LPT coverplate 26. Tube 28 is not annular, andinterturbine area 12 and gas turbine engine 10 can include multipletubes 28 spaced circumferentially around annular interturbine area 12.Tube 28 is configured to provide cooling air to interturbine area 12and, more specifically, to LPT coverplate 26 and LPT disk 16. Tube 28can be rotating or nonrotating, and can have curves, angles, or otherconfigurations to convey cooling air from a cool air source tointerturbine area 12. Tube 28 can include other features, such assealing surfaces and seals. Interturbine area 12 can also include aconfiguration in which tube 28 is not present and cooling air isconveyed to interturbine area 12 another way. Further, tube 28 caninclude other features and configurations not shown or explicitlydiscussed in this disclosure.

FIG. 2A is an enlarged cross-sectional view of a flow metering andretention system in interturbine area 12 of gas turbine engine 10, FIG.2B is a first cross-sectional perspective view of the flow metering andretention system, and FIG. 3 is a second cross-sectional perspectiveview of the flow metering and retention system without showing HPTcoverplate 24.

Flow metering and retention system 34 includes LPT disk 16, LPTcoverplate 26, HPT coverplate 24, and ring 36. LPT disk 16 includes LPTdisk teeth 38 and LPT disk teeth groove 40 (shown in FIGS. 2B and 3) atLPT interface 32, member 42, slot 17 with radially outer side 17 aformed by LPT interface 32 and radially inner side 17 b formed by member42, and LPT disk wear surface 46. HPT coverplate 24 includes arm 25,which has rib 48 and HPT coverplate wear surface 50. LPT coverplate 26includes LPT coverplate teeth 52 and LPT coverplate teeth groove 54(shown in FIGS. 2B and 3) at LPT interface 32. Also shown in FIGS. 2A,2B, and 3 are HPT disk 14 and shaft 18. Cooling air flow F flows throughslot 17 between HPT coverplate 24 and LPT disk 16.

Ring 36 is at LPT interface 32, which is the location at which LPT disk16 and LPT coverplate 26 interact. Ring 36 has an annular shape that canbe constructed from any material. Ring 36 can be a spiral ring, a splitring, or another type of annular member. However, ring 36 should havesufficient structural integrity and rigidity to hold LPT disk teeth 38and LPT coverplate teeth 52 adjacent to one another and ensure the twocomponents remain interlocked. As shown in the disclosed embodiment,ring 36 is a spiral ring with two annular loops/spirals. Ring 36 caninclude other features and configurations not shown or explicitlydiscussed in this disclosure.

As most easily seen in FIG. 3, LPT disk 16 includes LPT disk teeth 38that extend axially forward and circumferentially alternate with LPTcoverplate teeth 52. LPT disk teeth 38 can include any number ofindividual teeth that alternate with LTP coverplate teeth 52 to extendcircumferentially around the annular LPT disk 16 at LPT interface 32.LPT disk teeth 38 can extend axially any length, with individual teethbeing able to extend axially an equal length or a different length thanadjacent LPT disk teeth 38 and/or LPT coverplate teeth 52 (with LPTcoverplate teeth 52 between LPT disk teeth 38). LPT disk teeth 38 canextend axially a sufficient length to allow for LPT disk teeth groove 40and ring 36 therein.

LPT coverplate 26 includes LPT coverplate teeth 52 that extend radiallyinward from LPT coverplate 26 and circumferentially alternate with LPTdisk teeth 38. As with LPT disk teeth 38, LPT coverplate teeth 52 caninclude any number of individual teeth that alternate with LPT diskteeth 38 to extend circumferentially around the annular LPT coverplate26 at LPT interface 32. LPT coverplate teeth 52 can extend radiallyinward any distance, but as shown in the disclosed embodiment the LPTcoverplate teeth 52 extend inward a distance approximately equal to theradial thickness of LPT disk teeth 38. Further, the LPT coverplate teeth52 can have any axial length, with individual teeth being able to extendaxially an equal length or a different length than adjacent LPTcoverplate teeth 52 and/or LPT disk teeth 38 (with LPT disk teeth 38between LPT coverplate teeth 52). LPT coverplate teeth 52 can extendaxially a sufficient length to allow for LPT coverplate teeth groove 54and ring 36 therein.

LPT disk teeth 38 can include LPT disk teeth groove 40, and LPTcoverplate teeth 52 can include LPT coverplate teeth groove 54. LPT diskteeth groove 40 and LPT coverplate teeth groove 54 extend radially andare configured to form one circumferentially continuous groove at LPTinterface 32 to house at least a portion of ring 36. The one continuousgroove formed by LPT disk teeth groove 40 and LPT coverplate teethgroove 54 can have any radial depth suitable to house all or a portionof ring 36, and can have any axial length configured to allow ring 36 tofit within. Ring 36 can be held within the one continuous groove formedby LPT disk teeth groove 40 and LPT coverplate teeth groove 54 by afastener or some other retaining means, including adhesive or frictionby being sized to be squeezed within the groove. LPT disk teeth 38, LPTdisk teeth groove 40, LPT coverplate teeth 52, and LPT coverplate teethgroove 54 can include other features and configurations not shown orexplicitly discussed in this disclosure.

Ring 36 is in position within the one continuous groove formed by LPTdisk teeth groove 40 and LPT coverplate teeth groove 54 to extendentirely circumferentially around LPT interface 32 and adjacent to LPTdisk teeth 38 and LPT coverplate teeth 52. Ring 36 positioned within thegroove is configured to prevent axial movement of LPT disk 16 relativeto LPT coverplate 26 to retain the two components axially adjacent toone another. Further, with LPT disk teeth 38 and LPT coverplate teeth 52alternating in a circumferential direction, LPT disk 16 and LPTcoverplate 26 are prevented from circumferential movement relative toone another. And with LPT disk 16 being at least partially radiallyinward from LPT coverplate 26, LPT disk 16 and LPT coverplate 26 arealso prevented from radial movement relative to one another. Thus, flowmetering and retention system 34 is configured to prevent movement(i.e., retain) of LPT disk 16 relative to LPT coverplate 26 along threedegrees of freedom.

Another feature of flow metering and retention system 34 is provided bythe configuration of ring 36 in relation to arm 25 of HPT coverplate 24and slot 17 of LPT disk 16. Arm 25 extends axially rearward from HPTcoverplate 24 into slot 17 on axially forward side 16 c of LPT disk 16.Arm 25 is annular in shape with a cross section that can have a flatradially outer side adjacent to ring 36 and radially outer side of slot17, with HPT coverplate wear surface 50 being located on the flatradially outer side of arm 25. HPT coverplate wear surface 50 can be acoating or another component/configuration that protects arm 25 frombecoming damaged if ring 36 were to contact arm 25. On a radially innerside of arm 25 is rib 48, which is a radially inward extending flangethat extends circumferentially around annular arm 25. Rib 48 on arm 25is adjacent to and radially outward from radially inner side 17 b ofslot 17.

Slot 17 is annular in shape and is a U-shaped cross-sectional opening inaxially rearward side near radially inner side 16 b of LPT disk 16. Slot17 has radially outer side 17 a formed by LPT disk teeth 38 (and LPTcoverplate teeth 52) that is adjacent to and radially outward from theflat radially outer side of arm 25. Radially inner side 17 b of slot 17is formed by member 42 of LPT disk 16 that is adjacent to and radiallyinward from rib 48. Slot 17 provides an opening into which arm 25 of HPTcoverplate 24 extends, with cooling air flow F flowing through a gapbetween slot 17 and arm 25. On radially inner side 17 b of slot 17 isLPT disk wear surface 46, which can be a coating or anothercomponent/configuration that protects rib 48 of arm 25 from becomingdamaged if arm 25 of HPT coverplate 24 were to contact radially innerside 17 b of slot 17.

With ring 36 extending radially inward from LPT disk teeth 38 and LPTcoverplate teeth 52 toward arm 25, a first metering point is formed tometer cooling air flow F flowing between LPT disk 16 and HPT coverplate24. The first metering point is a choke point of reduced cross-sectionalflow area along the flow path of cooling air flow F from tube 28 toshaft 18. The first metering point ensures that the cooling air withininterturbine area 12 remains at an increased pressure to better providecooling capacity to LPT disk 16, LPT coverplate 26, and the othercomponents within interturbine area 12. With rib 48 extending radiallyinward from arm 25 towards radially inner side 17 b, a second meteringpoint is formed to meter cooling air flow F flowing between LPT disk 16and HPT coverplate 24. Like the first metering point, the secondmetering point is a choke point of reduced cross-sectional flow areaalong the flow path of cooling air flow F from tube 28 to shaft 18. Thesecond metering point works in conjunction with the first metering pointto ensure that the cooling air within interturbine area 12 remains at anincreased pressure.

Flow metering and retention system 34 having two metering points createsredundancy and ensures that a choke point is present along the flow pathof cooling air flow F even when HPT coverplate 24 (and arm 25) moveradially with regards to LPT disk 16 (and slot 17). During a situationin which HPT coverplate 24 moves radially outward relative to LPT disk16, a gap between ring 36 and arm 25 narrows, causing the choke point tobe at the first metering point and causing a gap between rib 48 andradially inner side 17 b of slot 17 to widen. Thus, the first meteringpoint functions to meter cooling air flow F and ensures the pressure ofcooling air within interturbine area 12 remains increased. During asituation in which HPT coverplate 24 moves radially inward relative toLPT disk 16, the gap between ring 36 and arm 25 widens, but the gapbetween rib 48 and radially inner side 17 b of slot 17 narrows, causingthe choke point to be at the second metering point. Thus, the secondmetering point functions to meter cooling air flow F and ensures thepressure of cooling air within interturbine area 12 remains increased.If no radial movement of HPT coverplate 24 (and/or HPT disk 14) relativeto LPT disk 16 can occur within gas turbine engine 10, than a flowmetering and retention system 34 with two metering points may not beneeded and only one metering point may be necessary.

Ring 36 forming the first metering point also provides a buffer betweenLPT disk 16 and HPT coverplate 24 to prevent damage to either componentif LPT disk 16 and HPT coverplate 24 were to contact one another. Duringsuch a situation, ring 36 (which can be made from a softer, lessexpensive material than LPT disk 16 and HPT coverplate 24) wouldfunction as a sacrificial component that would take on the resultantwear so that LTP disk 16 and HPT coverplate 24 would not become damaged.The wear is a result of the contact between two oppositely rotatingcomponents (or two components that are rotating at different speedsand/or one component being nonrotating). With ring 36 being smaller andless expensive to replace than LPT disk 16 and HPT coverplate 24, if anycomponent is to become damaged during operation, damage to ring 36 ismore desirable than damage to LPT disk 16 and HPT coverplate 24.

As discussed above, the configuration of ring 36 and the othercomponents provides at least three functions in flow metering andretention system 34. First, ring 36 within LPT disk teeth groove 40 andLPT coverplate teeth groove 54 provides axial retention of LPT disk 16and LPT coverplate 26 to ensure the two components remain adjacent toone another. The circumferential alternating teeth of LPT disk teeth 38and LPT coverplate teeth 52 provide circumferential retention of LPTdisk 16 and LPT coverplate 26 to ensure the two component rotate inunison, while the configuration in which at least a portion of LPT disk16 is radially within LPT coverplate 26 provides radial retention toensure the two components remain radially adjacent to one another. Thus,ring 36 aids in ensuring that LPT coverplate 26 is retained in relationto LPT disk 16. Second, ring 36 extends radially inward into the flowpath of cooling air flow F flowing between LPT disk 16 and HPTcoverplate 24 to provide the first metering point to ensure the pressureof cooling air flow F within interturbine area 12 remains elevated toprovide sufficient cooling to LPT disk 16, LPT coverplate 26, and theother components within interturbine area 12. Third, ring 36 acts as abuffer between LPT disk 16 and arm 25 of HPT coverplate 24 to preventthe two components from contacting one another and causing damage to oneanother. Thus, with ring 36 having multiple functions within flowmetering and retention system 34, interturbine area 12 of gas turbineengine 10 can be more efficient and compact, resulting in gas turbineengine 10 that is lighter and more efficient.

Discussion of Possible Embodiments

The following are non-exclusive descriptions of possible embodiments ofthe present invention.

A system for a gas turbine engine includes a high pressure turbine disk,a high pressure turbine coverplate, and low pressure turbine disk, a lowpressure turbine coverplate, an interface between the low pressureturbine disk and the low pressure turbine coverplate, and a ring. Thehigh pressure turbine coverplate is axially rearward of the highpressure turbine disk and has an arm that extends axially rearward. Thelow pressure turbine disk is axially rearward of the high pressureturbine coverplate and has a slot into which the arm of the highpressure turbine coverplate extends. The low pressure turbine coverplateis at least partially between the high pressure turbine coverplate andthe low pressure turbine disk. The interface is radially outward fromthe arm of the high pressure turbine coverplate and has a groove. Thering is within the groove at the interface and extending radially inwardtowards the arm of the high pressure turbine coverplate with the ringbeing configured to prevent axial movement of the low pressure turbinecoverplate relative to the low pressure turbine and to form a firstmetering point to meter air flowing between the high pressure turbinecoverplate and the low pressure turbine disk.

The system of the preceding paragraph can optionally include,additionally and/or alternatively, any one or more of the followingfeatures, configurations and/or additional components:

The interface includes low pressure turbine disk teeth and low pressureturbine coverplate teeth that alternate and interlock in acircumferential direction, each of the low pressure turbine disk teethand the low pressure turbine coverplate teeth include the groove withthe ring positioned within the groove to prevent movement of the lowpressure turbine disk teeth relative to the low pressure turbinecoverplate teeth.

The ring is at least one spiral ring that is annular in shape.

The arm of the high pressure turbine coverplate includes a radiallyinward extending rib configured to form a second metering point to meterair flowing between the high pressure turbine coverplate and the lowpressure turbine disk.

The rib meters the air flowing between the high pressure turbinecoverplate and the low pressure turbine disk to cause air adjacent tothe low pressure turbine coverplate to be at a greater pressure than airdownstream from the rib.

The low pressure turbine disk and the low pressure turbine coverplateare rotatable in a direction that is opposite a direction of rotation ofthe high pressure turbine disk and the high pressure turbine coverplate.

A shaft radially inward from the high pressure turbine disk and the lowpressure turbine disk, wherein the low pressure turbine disk and theshaft interlock such that the low pressure turbine disk, the lowpressure turbine coverplate, and the shaft are rotatable in unison.

The ring provides a buffer to prevent the arm of the high pressureturbine coverplate from contacting the low pressure turbine disk.

The low pressure turbine coverplate includes at least one cooling airhole configured to allow cooling air to reach the low pressure turbinedisk.

The ring meters the air flowing between the high pressure turbinecoverplate and the low pressure turbine disk to cause air adjacent tothe low pressure turbine coverplate to be at a greater pressure than airdownstream from the ring.

A flow metering and retention system includes a first disk that isannular in shape surrounding a centerline and extending axially alongthe centerline, a first coverplate axially rearward of the first diskwith the first coverplate having an axially rearward extending arm, asecond disk that is annular in shape surrounding the centerline andrearward of the first coverplate, a second coverplate at least partiallybetween the first coverplate and the second disk; and a ring adjacent tothe radially outer side of the slot of the second disk. The second diskhas a slot into which the arm of the first coverplate extends with theslot having a radially outer side and a radially inner side, and thering is configured to meter air flowing between the radially outer sideof the slot and the arm of the first coverplate.

The flow metering and retention system of the preceding paragraph canoptionally include, additionally and/or alternatively, any one or moreof the following features, configurations and/or additional components:

The second disk includes a groove in the radially outer side of the slotwith the ring being at least partially within the slot.

The second disk includes first teeth at the radially outer side of theslot and the second coverplate includes second teeth that are adjacentto and circumferentially alternate with the first teeth of the seconddisk.

The first teeth of the second disk and the second teeth of the secondcoverplate include an annular groove with the ring being at leastpartially within the groove to retain the second coverplate adjacent tothe second disk.

The arm of the first coverplate includes a rib that extends radiallyinward to meter air flowing between the rib and the radially inner sideof the slot of the second disk.

The ring is a spiral ring.

A shaft extending axially along the centerline.

The second disk is adjacent to the shaft and interlocks with the shaftto be configured to rotate in unison with the shaft.

The second coverplate includes at least one cooling air hole to allowcooling air to reach the second disk.

The first disk and the first coverplate are configured to rotate in afirst direction and the second disk and the second coverplate areconfigured to rotate in a second direction that is opposite the firstdirection.

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

1. A system for a gas turbine engine extending along a centerline, thesystem comprising: a high pressure turbine disk; a high pressure turbinecoverplate axially rearward of the high pressure turbine disk and havingan arm that extends axially rearward; a low pressure turbine diskaxially rearward of the high pressure turbine coverplate, the lowpressure turbine disk having a slot into which the arm of the highpressure turbine coverplate extends; a low pressure turbine coverplateat least partially between the high pressure turbine coverplate and thelow pressure turbine disk; an interface between the low pressure turbinedisk and the low pressure turbine coverplate, the interface beingradially outward from the arm of the high pressure turbine coverplateand having a groove; and a ring within the groove at the interface andextending radially inward towards the arm of the high pressure turbinecoverplate, the ring being configured to prevent axial movement of thelow pressure turbine coverplate relative to the low pressure turbine andto form a first metering point to meter air flowing between the highpressure turbine coverplate and the low pressure turbine disk.
 2. Thesystem of claim 1, wherein the interface includes low pressure turbinedisk teeth and low pressure turbine coverplate teeth that alternate andinterlock in a circumferential direction, each of the low pressureturbine disk teeth and the low pressure turbine coverplate teeth includethe groove with the ring positioned within the groove to preventmovement of the low pressure turbine disk teeth relative to the lowpressure turbine coverplate teeth.
 3. The system of claim 1, wherein thering is at least one spiral ring that is annular in shape.
 4. The systemof claim 1, wherein the arm of the high pressure turbine coverplateincludes a radially inward extending rib configured to form a secondmetering point to meter air flowing between the high pressure turbinecoverplate and the low pressure turbine disk.
 5. The system of claim 4,wherein the rib meters the air flowing between the high pressure turbinecoverplate and the low pressure turbine disk to cause air adjacent tothe low pressure turbine coverplate to be at a greater pressure than airdownstream from the rib.
 6. The system of claim 1, wherein the lowpressure turbine disk and the low pressure turbine coverplate arerotatable in a direction that is opposite a direction of rotation of thehigh pressure turbine disk and the high pressure turbine coverplate. 7.The system of claim 1, further comprising: a shaft radially inward fromthe high pressure turbine disk and the low pressure turbine disk,wherein the low pressure turbine disk and the shaft interlock such thatthe low pressure turbine disk, the low pressure turbine coverplate, andthe shaft are rotatable in unison.
 8. The system of claim 1, wherein thering provides a buffer to prevent the arm of the high pressure turbinecoverplate from contacting the low pressure turbine disk.
 9. The systemof claim 1, wherein the low pressure turbine coverplate includes atleast one cooling air hole configured to allow cooling air to reach thelow pressure turbine disk.
 10. The system of claim 1, wherein the ringmeters the air flowing between the high pressure turbine coverplate andthe low pressure turbine disk to cause air adjacent to the low pressureturbine coverplate to be at a greater pressure than air downstream fromthe ring.
 11. A flow metering and retention system comprising: a firstdisk that is annular in shape surrounding a centerline and extendingaxially along the centerline; a first coverplate axially rearward of thefirst disk with the first coverplate having an axially rearwardextending arm; a second disk that is annular in shape surrounding thecenterline and rearward of the first coverplate, the second disk havinga slot into which the arm of the first coverplate extends with the slothaving a radially outer side and a radially inner side; a secondcoverplate at least partially between the first coverplate and thesecond disk; and a ring adjacent to the radially outer side of the slotof the second disk and configured to meter air flowing between theradially outer side of the slot and the arm of the first coverplate. 12.The flow metering and retention system of claim 11, wherein the seconddisk includes a groove in the radially outer side of the slot with thering being at least partially within the slot.
 13. The flow metering andretention system of claim 11, wherein the second disk includes firstteeth at the radially outer side of the slot and the second coverplateincludes second teeth that are adjacent to and circumferentiallyalternate with the first teeth of the second disk.
 14. The flow meteringand retention system of claim 13, wherein the first teeth of the seconddisk and the second teeth of the second coverplate include an annulargroove with the ring being at least partially within the groove toretain the second coverplate adjacent to the second disk.
 15. The flowmetering and retention system of claim 11, wherein the arm of the firstcoverplate includes a rib that extends radially inward to meter airflowing between the rib and the radially inner side of the slot of thesecond disk.
 16. The flow metering and retention system of claim 11,wherein the ring is a spiral ring.
 17. The flow metering and retentionsystem of claim 11, further comprising: a shaft extending axially alongthe centerline.
 18. The flow metering and retention system of claim 17,wherein the second disk is adjacent to the shaft and interlocks with theshaft to be configured to rotate in unison with the shaft.
 19. The flowmetering and retention system of claim 11, wherein the second coverplateincludes at least one cooling air hole to allow cooling air to reach thesecond disk.
 20. The flow metering and retention system of claim 11,wherein the first disk and the first coverplate are configured to rotatein a first direction and the second disk and the second coverplate areconfigured to rotate in a second direction that is opposite the firstdirection.